Stabilizing means for a rotary reamer



Jan. 28, 1964 M. HoERER STABILIZING MEANS FOR A ROTARY REAMER Filed Sept. 10, 1962 .n.x...4,n. I.. C 4

aired States 'Ihe present invention relates generally to reaming apparatus and has particular reference to stabilizing means whereby 4a rotary abrasive type reaming tool, such as is employed for imparting tapered, frusto-conical or other shapes tothe rim regions or edges of holes that have been previously drilled in ceramic or other brittle materials, is prevented from chattering due to eccentric wobbl-ing thereof with the result -that the material undergoing abrasion is less likely to be subject to chipping.

Occasions arise where it is desirable or necessary to provide in marble, granite, slate :and similar brittle materials, holes which have slanting or tapered sides. An example of this is in connection with tables which are employed `for playing pocket billiards and are commonly referred to as pool tables. The playing surfaces oi professional and commercial pool tables of the better grade are invariably of felt-covered slate or marble and the holes which are provided at the corners and sides of such tables are provided with frusto-conical or sloping sides to the end that clearance for entry and dropping of the balls into the pockets will be established as soon as the balls encounter the rims of the holes. The pocket areas, therefore, need not project unduly inwardly of the table rails nor need the height of the rails be made unduly high. Heretofore, inthe manufacture of a pool `and similar game table having a rel-atively (thick slate or marble slab rfor its playing surface, it has been the practice in the creation of tapered holes in the slab, first, to drill cylindrical holes .through the sl-ab by 'way of a conventional core drill and, thereafter, to taper the holes by chipping away the slate or marble material around the holes by way of a conventional hand tool, such as -a chisel, gouge, reaming iile or the like. These operations have required the use of highly skilled labor and, in addition, they have been time-consuming, thereby `adding lappreciably to the cost of producing lthe pool tables. Efforts to dispense with the use of such skilled labor by the use of suitably lshaped abrasive reamers have not been satisfactory, even when diamond abrasive reamers have been employed, this being due to chattering of the reamers `against the sides of the holes undergoing shaping and 1a consequent chipping of the material being worked upon, or even more serious, the creation of cracks in the slabs. Due to the proximity of the holes undergoing Teaming to the edges of the slab, the use of such power-driven reamers results in breaking of the connecting webs along the outside edges of the holes.

The present invention is designed to overcome the abovenoted limitations that :are attendant upon the reaming of holes in marble, slate, granite and similar materials, especially in slabs formed of such materials. Toward this end, the invention contemplates the provision of a novel stabilizing means whereby the rotary spindle and the abrasive-type reaming tool which is carried thereby are given reaction support against eccentric or other wobbling during advancement thereof toward the work, this stabilizing means assuming the form of a novel piloting arrangement whereby the actual roaming tool finds piloting support in the bed plate of the drill press or other machine which is employed for rotating the reaming tool.

A conventional pilot support for the forward end of an advancing reaming, honing or similar abrasive tool establishes reaction forces which are applied to the tool in the central or axial region thereof. Such a pilot supl @,205 Patented dan. 2Q, 1964 port is satisfactory for the roaming of small diameter holes o r bores but, where large holes are concerned, the application of piloting reaction force to the central region of ythe abrasive tool will not altogether eliminate chattering o f the tool against the side of `the hole undergoing abr-asion. According to the present invention, a firmer piloting support than has heretofore been provided for the forward end of a rotary abrasive-type roaming tool is provided, such support utilizing a relatively massive antifriction thrust bearing which is alixed to the bed plate of the drill press. The thrust bearing serves rotatably to support a reaction hub which is coaxial with the toolcarrying spindle and guide posts project upwardly from the outer marginal peripheral portion yof the reaction hub and extend into guide bores which are provided in the peripheral region of the abrasive tool where radial reaction forces 'are applied to the tool and, consequently, to the spindle which drives the tool, these -forces being effective in close proximity to the annular working abrasive area of the tool. By such an arrangement, any flexibility which may be inherent in either the spindle or in the body of the abrasive tool will not operate to allow lateral displacement of the abrasive working area or :areas of the tool.

The provision of a stabilizing means for a rotary rearner such as has briely been outlined above being among the principal objects of the invention, numerous other objects yand advantages will become readily apparent as a consideration of the following detailed description.

ln the accompanying single sheet of drawings forming apart of this specication, one illustrative embodiment of the invention has been shown.

ln these drawings:

FIG. l is a fragmentary sectional View taken substantially centrally and vertically through a rotary abrasivetype reaming tool and showing the tool in operative position before descending upon a ceramic slab for holeroaming purposes;

FIG. 2 is a sectional View similar to FIG. l but showing the tool in the position it assumes at the end of a reaming operation; and

FIG. 3 is a reduced sectional view taken along the line 3 3 of FlG. 1.

Referring now to the drawings in detail, the stabilizing means of the present invention has, for exemplary purposes, been shown as being operatively applied to a reaming tool lll; Tlhe latter is of the type which is em- .ployed for the purpose of rearning out the cylindrical wall l2 of a hole l which has previously been drilled in a slab lo of ceramic material, such :as slate or marble, to the end that the wall surface of the hole is made frusto-conical as indicated at 18 in FlG. 2.

The reaming operation is carried out by way of a conventional drill press which serves to rotate the tool le and, at the same time, feed the tool toward the work, namely, the slab lr6. Accordingly, the slab `le is supported on a spacer sheet 26 which is preferably in the form of a sheet of plywood and, in turn, is supported upon the bed plate or table 22 of the ldrill press. An oversize hole 2d is formed in the plywood sheet and the sheet is so positioned that this hole `is in vertical register and axial alignment with the rotating chuck Ze of the drill press. The details of the drill press have not been shown and only the bed plate 22 and the chuck 26 have been illustrated herein. It will be understood that the drill press is of conventional design and includes manual means whereby the chuck 26, in connection with rotation thereof, may be moved vertically toward and away from the bed plate 22 in `the usual manner of operation of a dri-ll press,` The slab 16 is supported upon the plywood sheet 21:: with the previously drilled hole la in register with the hole 2d in passed completely through the slab 16 and the mean diameter of the reamed wall 18 has assumed the desired or predetermined dimension as shown in FIG. 2. It will be understood, of course, that prior to performance of the downward operative abrasive stroke of the reaming tool lll), the operator will, before effecting rotation of the drill press spindle, lower the chuck, the spindle and the tool bodily as a unit and cause the upper ends of the guide posts 64 to enter the holes 68. After such entry of the guide posts into the holes, the drill press may be started to rotate the chuck 26 and commence resultant rotation of the tool 10, after which a drive will be established for the reaction hub Si) which will rotate in unison with the tool during the actual reaming operation. After the reaming operation is complete, the operator will release the operating handle of the drill press and the chuck 26 and the tool 1l) will automatically be restored to their initial elevated positions under the influence of the compression springs 74.

If the slab 16 undergoing treatment is relatively massive, as if, for example, the one inch thick marble or slate slab of a regulation sized pocket billiard table, it may be necessary to remove the stabilizing assembly 49 after each hole has been roamed so that the slab may be repositioned on the bed plate 22 for reaming of the next hole. Accordingly, the screw 61 which constitutes the sole means for securing the assembly 49 in its operative position may be provided with an Allen type socket Si) to facilitate its removal by use of an Allen wrench. Thus, for each hole which is reamed, the assembly 49 will be removed and replaced. On the other hand, if the slab is relatively light and easily portable, the assembly 49 may be left permanently in position on the bed plate 22 and the slab 16 lifted over the assembly for shifting or removal purposes, the stroke of the drill press chuck being such as to afford the necessary clearance between the tool and the assembly 49 for such shifting or removal of the slab.

The invention is not to be limited to the exact arrangement of parts shown in the accompanying drawings or described in this specification as Various changes in the details of construction may be resorted to without departing from the spirit or scope of the invention. For example, while the reaming tool which is illustrated and described has been designed specifically for imparting a frusto-conical configuration to the inside Wall surfaces of previously drilled holes in marble, slate, granite and similar ceramic materials, it is obvious that, by suitable modification of the shape of the abrasive surfaces of such tool, other configurations may be imparted to the wall surfaces of cylindrical holes or other openings in such materials. Therefore, only insofar as the invention has particularly been pointed out in the accompanying claims is the same to be limited.

Having thus described the invention what I claim as new and desire to secure by Letters Patent is:

1. An apparatus adapted to ream the inside wall surface of a preformed hole in a ceramic slab and comprising a bed plate for supporting the slab in a horizontal position, a reaming tool mounted for rotation about a vertical axis and vertically movable bodily toward and away from said bed plate, a peripheral abrasive surface formed on said tool and adapted to enter the hole for wall-reaming purposes during vertical descent of the tool toward the bed plate, a stabilizing reaction hub mounted for rotation on said bed plate about an axis coincident with the vertical axis of rotation of the reaming tool, and a plurality of circumferentially spaced guide posts projecting upwardly from said hub at eccentric regions thereon, said tool being provided with a plurality of guideways within which said guide posts are axially slidable during descent of the tool toward the bed plate.

2. `An apparatus as set forth in claim 1 and wherein the guide posts are cylindrical and the guideways are in the form of cylindrical bo-res within which the guide posts are slidable with a snug tit.

3. An apparatus as set forth in claim 2 and including, additionally, compression springs surrounding the guide posts and having their upper ends bearing against the rearning tool and their lower ends bearing against the reaction hub.

4. An apparatus as set forth in claim 2 and wherein the guide posts are two in number and are disposed diametrically opposite one another on the reaction hub, and the cylindrical bores within which said guide posts are receiver are disposed in the penipheral reg-ions of the reaming tool.

5. An apparatus adapted fto ream the inside wall surface of a hole in a ceramic slab and comprising a bed plate for supporting the slab in a horizontal position, a reaming tool mounted for rotation about a vertical axis and vertically movable bodily toward and away from said bed plate, a peripheral abrasive surface formed on said tool and adapted to enter the hole for wall-roaming i urposes during vertical descent of the tool toward the bed plate, stabilizing means for said tool mounted on the bed plate and engageable with the tool for preventing eccen-tric wobbling of the latter, said stabilizing means comprising a ball bearing assembly including inner and outer races, a fastening screw removably securing said inner race to the bed plate in axial coincidence with the reaming tool, a reaction hub telescopically received over said outer race `and rotatable bodily therewith, and a plurality of ci-rcumferentially spaced guide posts projecting upwardly from said hub at eccentric regions thereon, said tool being provided with a plurality of guideways within which said guide posts are axially lslidable during `descent of the tool toward the bed plate.

6. An apparatus as set forth in claim 5 and wherein the guide posts are cylindrical and the guideways are in the foi-in of cylindrical bores within rwhich the guide posts are slidable with a snug fit.

7. An apparatus as set forth in claim 6 and wherein the guide posts are two in number and are disposed diametrically opposite to one another on the hub, and the cylindrical bores within which said guide posts are received are `disposed in the peripheral regions of the ream'in-g tool.

8. An apparatus as set forth in claim 7 and including, additionally, compression springs surrounding said guide posts and having their upper ends bearing against the reaming tool and at their lower ends bearing against the hub.

References Cited in the tile of this patent UNITED STATES PATENTS 1,774,898 Fleming Sept. 16, 1930 

1. AN APPARATUS ADAPTED TO REAM THE INSIDE WALL SURFACE OF A PREFORMED HOLE IN A CERAMIC SLAB AND COMPRISING A BED PLATE FOR SUPPORTING THE SLAB IN A HORIZONTAL POSITION, A REAMING TOOL MOUNTED FOR ROTATION ABOUT A VERTICAL AXIS AND VERTICALLY MOVABLE BODILY TOWARD AND AWAY FROM SAID BED PLATE, A PERIPHERAL ABRASIVE SURFACE FORMED ON SAID TOOL AND ADAPTED TO ENTER THE HOLE FOR WALL-REAMING PURPOSES DURING VERTICAL DESCENT OF THE TOOL TOWARD THE BED PLATE, A STABILIZING REACTION HUB MOUNTED FOR ROTATION ON SAID BED PLATE ABOUT AN AXIS COINCIDENT WITH THE VERTICAL AXIS OF ROTATION OF THE REAMING TOOL, AND A PLURALITY OF CIRCUMFERENTIALLY SPACED GUIDE POSTS PROJECTING UPWARDLY FROM SAID HUB AT ECCENTRIC REGIONS THEREON, SAID TOOL BEING PROVIDED WITH A PLURALITY OF GUIDEWAYS WITHIN WHICH SAID GUIDE POSTS ARE AXIALLY SLIDABLE DURING DESCENT OF THE TOOL TOWARD THE BED PLATE. 